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Little Brown Bat - Watchable Wildlife

Did You Know?

little brown bat roosting in a cave
Little brown bat - Myotis lucifugis
  • Bats are the only mammals that can fly.
  • They are insect-eating machines, eating thousands of mosquitoes and other flying insects in a single night!
  • Bats use echolocation (rapid pulses of sound that bounce off an object) to detect and catch insects. They scoop the insects up in their tail or wing membranes and then place them in their mouth. This is what gives them such an irregular flight pattern.
  • As temperatures decrease in the fall and the number of insects diminish, bats migrate to their hibernacula (place where animals hibernate) in caves or mines for the winter. During hibernation a bat will reduce its body temperature. It will slow its heart rate to only one beat every four or five seconds and rely on its stored fat reserves to survive until springtime.
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What to Watch for:

Size:

Little brown bats have a wingspan of 8-9 inches and a body length of 3-4½ inches with a 1 ½ inch forearm. On average, adults weigh less than half an ounce.

Appearance:

Bats are covered in a coat of silky cinnamon and dark brown hair and pale grey underneath. They have black hand-like wings.

Where to Watch:

In warmer months, during early dawn or at dusk, bats can be seen flying above and alongside trees as they dip and dive for insects. Looking up above a body of water in areas where flying insects are most abundant (lake, pond, stream, etc.), provides a good chance to spot bats.

During the winter, bats take shelter in caves and mines, but do not look for bats in these areas. Entering into caves or mines is dangerous without the proper knowledge or guidance. In addition, it is important not to disturb and awaken hibernating bats in the winter, because they will lose necessary fat reserves that they rely on to survive. White-nose syndrome is a serious disease in bat populations that can be spread from cave to cave by humans (see "More Information" below).

What to Listen for:

Bats make sounds by echolocation, which are generally too high pitched for the human ear to hear. You may be able to hear a click or squeak as they fly by directly overhead.

When to Watch:

When temperatures become warm enough in the spring, bats emerge from their hibernation sites to find an above-ground roost. Your best bet is to look for bats, approximately 30 minutes after sunset, from late spring to early autumn. When temperatures fall in autumn, the bats will return to their underground homes to hibernate.

More Information About Little Brown Bats:

bat box example
Homemade bat house

The Best Places to See Little Brown Bats:

Check out your local park or forested area, especially near water and along trails. Even your own backyard can be a great place to view bats if you have a collection of trees near your home!